Advanced Materials Research Vols. 383-390

Abstract: In dealing with the problem of the SAPF’s nonlinear and strong coupling model, the internal model control of three-phase four-leg active power filter based on online ANN method is studied in this paper. With the ANN’s nonlinear mapping ability of self-learning and self-organizing modeling, the inverse system can be approximated by online LS-SVM. In order to have a good linearization control effect, the internal model control based on ANN is proposed for the combined pseudo-linear system. This method can be used to design effective controllers for nonlinear system with unknown mathematical models. At last, the simulation results show that a good steady-state performance can be obtained under the improved method

Abstract: This note deals with the problem of stability for networked control system (NCS) with uncertain time-varying delay that is less than on sampling period. A new stability scheme was proposed. Using an Lyapunov function, less conservative stability sufficient condition was derived for such system based on liner matrix inequalities (LMs). Finally a numerical example shows the superiority of the method in this paper.

Abstract: A Z-source boost-buck rectifier topology has been proposed to overcome the limitation of the conventional voltage source rectifier which is a boost rectifier. Conventional Z-source rectifier topology’s lowest dc output voltage is limited because increasing the shoot-through duty ratio and the modulation index simultaneously to obtain low dc output voltage is contradictory with the principle that the sum of M and D must be lower than 1. To overcome this contradiction, this paper proposes a novel topology for Z-source rectifier which can obtain lower dc output voltage with power factor correction and less input harmonic current. This paper firstly analyzes the proposed topology and makes a comparison with the conventional one. At last, the simulation results will be presented and verify its outstanding buck capability.

Abstract: Consequences of dam-break are affected by many factors, which are of a certain degree of ambiguity. Influencing factors of dam-break consequences are summarized in this paper. At first, weights of influencing factors are determined by means of Analytic Hierarchy Process （AHP）, thereafter, the fuzzy hierarchy synthesis evaluation model for dam failure is developed. Finally, Qing Linjing reservoir located in Shenzhen of China is taken as a case. The fuzzy comprehensive evaluation for the risk analysis of dam-break and the risk grades of dam-break consequences are obtained. The results indicate that it is reasonable and valuable to evaluate the risk of dam-break by using fuzzy comprehensive evaluation.

Abstract: Due to its advantages, such as shock resistance, low power consumption, and so on, solid state drives are considered as a next generation storage device. And write amplification is a very import system parameter for evaluating performance. To simplify the analytical model of write amplification for solid state drives adopting page-level address translation mechanism, this paper proposes a probability model. Furthermore, numerical results based on our proposed probability model are also obtained. This paper can pose as a guideline for a first-order estimation of the write amplification for parameter ranges in solid state drives taking page mapping scheme.

Abstract: This paper addresses the feedback stabilization problem for quantized feedback control systems, where sensors and controllers are connected by a digital communication channel. A dynamic, logarithmic quantization scheme is proposed. It is shown that quantized feedback control problems can be converted to robust control problems. The proof techniques rely on the LMI approach. Simulation results show the validity of the proposed quantization policy.

Abstract: In order to optimize design on the iron beam sectional of the electricity transformer, a non-linear mathematical model is built to improve areas of every scale and the optimization scale is 14. Based on the principle of “equal precision designing” and GB/T 4249, the tolerance zone of the iron beam is set as the geometry tolerance of the diameter of the iron beam Ø650_o+^0.51+ and the inner tube Ø652^+0.028with the interval of 1mm.

Abstract: An AC servo driver speed adjusting system based on space vector pulse width modulation (SVPWM) is put forward. The principle of SVPWM and its software algorithm based on digital signal processor (DSP) are introduced in detail, and the structure of the system is designed. The simulation model of the system is built in Matlab, the simulation research provides theoretical basis for AC servo driver control performance.

Abstract: In the existing process of maneuvering target tracking, the target’s actual trajectory can not be foreseen precisely. A commonly attempt is under the assumption that the target’s trajectory is prefixed. The prefixed model is usually not inosculated with the target’s actual trajectory, and the target’s tracking precision can not be guaranteed. In this paper a parameter identification model is presented. This model identifies the target’s trajectory dynamically, adapts to the variation of working cycle, and covers kinds of possible state of the maneuvering target. An adaptive filtering is then employed to analyze the tracking. We call it as a whole adaptive tracking in this paper. Simulations verify that this adaptive tracking algorithm effectively improves the tracking precision.

Abstract: After rising the smoothness problem of the telescope low speed condition, we develop a new servo controlling method for large optical telescope that combine PID with repetitive controller. Analysis shows that this controller has a strong ability to overcome the periodical disruption and a rapid reaction to any action. Working with the improved repetitive controller can achieve a high precision. Practically, we reach to the target successfully.